<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <%  if(islogin){    %>
        <span>欢迎回来</sapn>
        <%  }else{   %>
        <button> 注册</button>  <button>登录</button>
        <%  }   %>
</body>
</html>